Touch-sensitive systems detect and respond to one or more points of contact with a touch-sensitive surface. For example, a touch-sensitive system may be incorporated within an electronic device in the form of a touch screen display that allows a user to both view and manipulate objects using one or more inputs that contact the touch screen.
An electrostatic stylus may be used to create the points of contact with the touch screen and continuous contact with the touch screen and movement over time may form a stroke of the stylus. The stylus may include a body that is the approximate size of a pen or pencil (e.g., around 150 mm in length and around 10 mm in diameter) and may include an electrically conductive electrode at or within its tip. In some implementations, the tip is not electrically conductive (e.g., a plastic-coated metallic tip). The tip is placed in contact with the touch screen, which includes a matrix of conductors (e.g., an array of conductors arranged in rows and columns, forming a two-dimensional array of row-column intersections, or a two-dimensional array of individual square sensor electrodes) to track movement of the electrostatic stylus tip and reproduce points of contact with the touch screen digitally onto the touch screen.
Some touch-sensitive systems may determine whether the stylus is touching a particular location in the matrix by measuring a capacitance from conductors physically close to the location of the electrically conductive tip of the stylus. As the stylus is moved across the touch screen, different conductors are used to track the physical location of the stylus. However, artifacts, errors, or anomalies may be introduced into the digitally reproduced stroke. Systems and methods for identifying and compensating for such anomalies would improve the quality of the digitally reproduced stroke.